U.S. patent number 6,049,293 [Application Number 08/860,768] was granted by the patent office on 2000-04-11 for remote control system.
Invention is credited to Hermanus Marinus Ignatius Koot, Peter Van Wees.
United States Patent |
6,049,293 |
Koot , et al. |
April 11, 2000 |
Remote control system
Abstract
A remote control system, has a transmitter and a battery-powered
receiver adapted for wirelessly receiving and processing
information from the transmitter. The receiver has a receiving
section adapted to be periodically switched ON and OFF in the
absence of a signal intended for that receiver and to remain
switched ON continuously in the presence of a signal intended for
that receiver, until that signal falls away. In the presence of a
signal intended for that receiver, an adjusting motor is energized
for adjusting the tilting position of slats of a blind.
Inventors: |
Koot; Hermanus Marinus Ignatius
(Montfoort, NL), Van Wees; Peter (Montfoort,
NL) |
Family
ID: |
19865412 |
Appl.
No.: |
08/860,768 |
Filed: |
August 20, 1997 |
PCT
Filed: |
January 03, 1996 |
PCT No.: |
PCT/NL96/00007 |
371
Date: |
August 20, 1997 |
102(e)
Date: |
August 20, 1997 |
PCT
Pub. No.: |
WO96/21286 |
PCT
Pub. Date: |
July 11, 1996 |
Foreign Application Priority Data
Current U.S.
Class: |
340/12.29;
348/734; 340/12.17; 340/12.16 |
Current CPC
Class: |
H04W
52/0229 (20130101); Y02D 70/26 (20180101); Y02D
30/70 (20200801) |
Current International
Class: |
H04B
1/16 (20060101); G08C 019/00 () |
Field of
Search: |
;340/825.69,825.72,825.44,636,661,825.63,825.59,825.67,825.65,825.57,825.31
;455/343 ;324/433 ;318/16,558 ;341/176 ;307/10.2 ;348/734 ;359/146
;367/197 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
0452154 |
|
Oct 1991 |
|
EP |
|
2255846 |
|
Nov 1992 |
|
GB |
|
9621286 |
|
Jul 1996 |
|
WO |
|
Primary Examiner: Zimmerman; Brian
Assistant Examiner: Jeanglaude; Jean B.
Claims
We claim:
1. A remote control system, comprising a transmitter and a receiver
for wirelessly receiving and processing information from the
transmitter;
wherein the receiver comprises a receiving section which is
periodically switched ON or OFF in the absence of a signal intended
for that receiver and to remain switched ON continuously in the
presence of a signal intended for that receiver, until that signal
falls away;
wherein the receiver comprises a control means for controlling the
receiving section; and
a memory with a predetermined number of bits defining an address of
the receiver,
the control means being provided with comparing means to compare
address bits in the received signal with the address bits in the
memory, whereafter the address bits in the memory are replaced by
the address bits in the received signal if the address bits in the
memory does not contain any address information or if the address
bits in the memory does not indicate a valid address.
2. A remote control system according to claim 1, wherein the
receiver examines the received signal at intervals during the ON
state and energizes a motor after each check period unit a next
check period if a signal intended for that receiver is present, and
to leave that motor deenergized during each check period.
3. A remote control system according to claim 1, wherein the
receiver remains switched ON during a wait time after said signal
has fallen away.
4. A remote control system according to claim 1, wherein a control
means of the receiver limits the current through the motor to a
predetermined maximum value so as to limit the maximum torque
producible by the motor at its output shaft.
5. A remote control system according to claim 1, wherein the motor
is positioned near, or in a headrail of a blind and is coupled to
an adjusting mechanism for slats of that blind.
6. A remote control system according to claim 1, wherein the
control means couples the motor to a supply source and limits the
current through the motor to a preset value.
7. A remote control system according to claim 1, wherein the
transmitter transmits a pulsed signal having a pulse length T.sub.P
and a pulse repetition period T.sub.R, and wherein a receiving
section of the receiver is switched ON, in the absence of a signal
intended for that receiver, for a period of time T.sub.ON which
satisfies T.sub.ON >T.sub.P, preferably T.sub.ON .gtoreq.T.sub.P
+T.sub.g, and subsequently is switched OFF for a period of time
T.sub.OFF which lasts considerably longer than T.sub.ON.
8. A remote control system according to claim 1, wherein the
transmitter and the receiver transmit receive and process a pulsed
signal of which each pulse comprises a predetermined number of
bits, of which each bit contains a square-wave signal B in one bit
half and no signal in the other bit half.
9. A receiver for use in a remote control system according to claim
1, wherein the receiver comprises a receiving section which is
periodically switched ON and OFF in the absence of a signal
intended for that receiver and remains switched ON continuously in
the presence of a signal intended for that receiver until that
signal falls away;
and wherein the receiver comprises control means for controlling
the receiving section; and
a memory with a predetermined number of bits defining an address of
the receiver, wherein the control means compares an addressing in
the received signal with these bits, and wherein the control means
copies the addressing in the received signal to said bits if the
memory is empty or does not contain a valid address.
10. A remote control system according to claim 3, wherein the
receiver examines the received signal at intervals during the ON
state and energizes a motor after each check period until a next
check period if a signal intended for that receiver is present;
leaving that motor deenergized during each check period; and
leaving that motor deenergized after each check period until a next
check period if no signal intended for that receiver is
present.
11. A blind comprising an adjusting mechanism for the slats
thereof, a motor for operating that adjusting mechanism, and a
receiver according to claim 1, wherein the receiver energizes the
motor in the presence of a signal intended for that receiver.
Description
The invention relates to a remote control system, comprising a
transmitter and a receiver adapted for wirelessly receiving and
processing information from the transmitter.
At present, it is generally known in practice to control equipment
remotely, utilizing a wireless communication path between a
transmitter to be operated by a user and a receiver coupled to the
equipment to be operated, for instance by means of infrared
radiation or ultrasonic waves.
In general, the transmitter is powered by one or more batteries
which are loaded only when the transmitter is being operated by the
user, so that the energy consumption of the transmitter is
relatively low. Further, it is normally not complicated to replace
these batteries when they are exhausted, precisely because the
transmitter is intended to be close at hand.
Normally, the remotely controlled appliance is an electric
appliance, for instance a household appliance such as a television
set, with the energy supply taking place via the mains. In such
cases the energy consumption of the receiver coupled to that
appliance hardly plays a role.
However, there are situations where the remotely controlled
appliance and the receiver coupled thereto are powered by one or
more batteries, without any connection with the mains. An example
of such a situation is a remotely controlled blind having a
battery-powered receiver. Within the framework of the present
application, by a "blind" is meant: a blinding system comprising an
assembly of mutually parallel slats, the slats being rotatable
about their longitudinal axes in order to cover for instance a
window in a variable manner. If the slats extend horizontally, the
term "venetian blinds" is also used. If the slats extend
vertically, the term "vertical blinds" is also used. Such
window-blinding systems are generally known, and the present
invention will hereinafter be explained for use in blinds. However,
it is explicitly noted that the present invention is not limited to
this use.
Since in the case of a remotely controlled blind having a
battery-powered receiver, the battery or batteries are disposed in
the proximity of the headrail of the blind, which makes it
troublesome to replace the battery or batteries, it is then
desirable that the necessity for replacing the battery or batteries
arise as rarely as possible. It is therefore desirable that the
energy consumption of the receiver be as low as possible.
The practical example described serves as an illustration of a
general objective of the present invention, i.e. the provision of a
receiver of control signals which has a lowest possible energy
consumption.
An important difference between the receiver and the transmitter is
that it is not known at the receiver end when the transmitter is
transmitting. Therefore the receiver must be able to receive
signals from the transmitter at all times. Accordingly, the
receiver must be standby continuously, i.e. must be in a watching
mode. Although in the watching mode the energy consumption of the
receiver is relatively low, consumption is not nil, so that the
battery discharges slowly but surely.
One way of reducing the energy consumption of the receiver is to
switch the receiver ON and OFF periodically. In the ON state, the
receiver checks whether signals are coming in from the transmitter.
If not, the receiver returns to the OFF state again, where the
receiver uses practically no energy.
A remote control system as described in the preamble of claim 1 is
known from U.S. Pat. No. 5,081,402.
In practice, a plurality of remotely controlled appliances (blinds)
may be present in one room. An object of the invention is to
provide a system in which these blinds may be controlled
individually by only one transmitter unit. More particularly, an
object of the invention is to provide a system in which each
individual receiver is adapted to learn which command signal is
intended for that specific receiver.
A particular object of the invention is to provide a remote control
system with a receiver which is particularly energy-saving, and
which is capable of performing an adjustment on the basis of the
time during which the transmitter is operated.
Still more in particular, the object of the invention is to provide
a remote control system wherein the receiver reacts relatively
promptly, i.e. to the user virtually directly, to the transmission
of a transmission signal or command.
Battery-powered receivers also involve the problem that the battery
powers both the receiver proper and a motor which is selectively
energized by that receiver, which motor, however, can be such a
load to the battery, in particular when the battery is almost
exhausted, that it may happen that as a consequence of the voltage
drop caused thereby, the receiver no longer acts properly. The
object of the invention is also to solve this problem.
To that end, a remote control system according to the invention has
the characteristics set forth in the claims.
These and other aspects, characteristics and advantages of the
present invention will be further explained by the following
description of a preferred embodiment of the apparatus according to
the invention, with reference to the accompanying drawings,
wherein:
FIG. 1 is a perspective view of a blind and a transmitter;
FIG. 2 illustrates the time intervals of some states;
FIG. 3A illustrates an example of a coding;
FIG. 3B shows a block diagram of a transmitter;
FIG. 4 shows a block diagram of a receiver;
FIG. 5 is comparable with FIG. 2 and illustrates some states in
more detail; and
FIG. 6 shows a flow diagram of the operation of a receiver.
Hereinafter, the invention will be described for use for the
operation of blinds. It is observed, however, that this use is only
an example, and that the invention is not limited to this
example.
FIG. 1 diagrammatically shows a blind 10, having a headrail 11 and
horizontal slats 12. The slats 12, generally having a bent cross
section, are at one longitudinal side attached to vertically
directed tilting cords 13 and are at the other longitudinal side
attached to vertically directed tilting cords 14. Mounted under the
bottom slat 12 is a bottom rail 15, which is not only attached to
the tilting cords 13 and 14, but also to a vertically directed
hoisting cord 16 extending centrally through the slats 12. The
tilting cords 13 and 14 are coupled to a tilting mechanism disposed
in the headrail 11, while the hoising cord 16 is coupled to a
hoisting mechanism disposed in the headrail 11. By operating the
hoisting mechanism, the slats 12 can be hoisted, i.e. the vertical
position of the bottom rail 16 can be changed. By operating the
tilting mechanism, the slats 12 can be tilted, i.e. the angle of
the slats 12 relative to the horizontal can be varied. As the
nature and construction of the hoisting mechanism and those of the
tilting mechanism do not constitute a subject of the present
invention, and a skilled person need not have knowledge thereof for
a proper understanding of the present invention, while, further,
such hoisting and tilting mechanisms are already known per se in
practice, they are not shown in the Figures and will not be further
described.
Further disposed in the headrail 11 of the blind 10 is an
electromotor 60 (not shown in FIG. 1 for the sake of simplicity),
of which electromotor an output shaft is coupled to the tilting
mechanism, so that the tilting of the slats 12 can be carried out
through excitation of the motor. As the manner in which the tilting
mechanism is coupled to the motor does not constitute a subject of
the present invention, and a skilled person need not have knowledge
thereof for a proper understanding of the present invention, while
it is further known in practice to operate a tilting mechanism by
means of a motor, as for instance appears from European patent
application 0,452,154, this will not be further described
either.
In order to be able to control the motor remotely, the blind 10
comprises a remote control mechanism according to the invention,
which is generally designated by the reference numeral 1. In the
embodiment shown, the remote control mechanism 1 comprises a
housing 21 which can be taken in the hand by a user, with at least
one group of two control buttons 22.sub.L and 22.sub.R. The button
22.sub.L serves to tilt the slats 12 to the left, while the button
22.sub.R serves to tilt the slats 12 to the right. The direction of
tilting corresponds to a direction of rotation of the motor, as
will be understood by a skilled person.
Disposed in the housing 21 is a transmitter 20 having an output 26
for generating a transmission signal which is diagrammatically
designated in FIG. 1 by 27. In FIG. 1, this transmitter 20 is
indicated only diagrammatically by a dotted rectangle in the
housing 21.
The remote control mechanism 1 further comprises a receiver mounted
in the headrail 11 of the blind 10, which is generally designated
by the reference numeral 30 in FIG. 1, for receiving the signal
transmitted by the transmitter 20, which receiver 30 is coupled to
the above-mentioned motor so as to optionally energize this motor
on the basis of the received signal.
As is further shown in FIG. 1, in the embodiment illustrated, the
housing 21 comprises three further groups of two control buttons
23.sub.L and 23.sub.R, 24.sub.L and 25.sub.L and 25.sub.R. These
buttons can be intended for operating other blinds, so that with
the embodiment shown it is possible to operate four blinds or four
groups of blinds independently of each other in one space. It will
be understood by a skilled person that the number of groups of two
control buttons may in principle by any number. In a preferred
embodiment, three groups of two control buttons 22.sub.L and
22.sub.R, 22.sub.L and 23.sub.R, 24.sub.L and 24.sub.R are intended
to control three different (groups of) blinds, and the fourth group
of two control buttons 25.sub.L and 25.sub.R is intended to control
all three (groups of) blinds simultaneously.
The operation of the remote control system according to the
invention is illustrated in FIG. 2, wherein operating conditions of
the transmitter 20, the receiver 30 and the motor 60 are
represented as functions of time. In the Figure, the ratios of
different durations to each other are not shown to scale.
The central line in FIG. 2 represents the operating condition of
the transmitter 20. During the period designated by Q, the
transmitter 20 does not transmit a signal; this period will be
referred to as the operating condition "REST". or quiescent
condition. During the period designated by S, the transmitter 20
does transmit a signal 27; this period will be referred to as the
operating condition "TRANSMIT", or transmitting condition. The
transmitter 20 reaches the transmitting condition when the user
operates one of the above buttons at the point of time t.sub.1, and
the transmitter 20 returns to the quiescent condition when the user
releases that button at the point of time t.sub.2. In other words,
the transmitter 20 is in the transmitting conditions as long as the
user keeps a button depressed.
During the transmitting condition, the transmitter 20 transmits
transmitting pulses P with a predetermined repeating period
T.sub.R, as is illustrated by the block-shaped configuration of the
central line in FIG. 2 in the interval S. Each transmitting pulse P
has a predetermined pulse length T.sub.P, and contains all
information in respect of a repeating command, as will be clarified
later on. More in particular, each transmitting pulse P contains
information in respect of the identity of the receiver for which
the command is intended and information in respect of the action to
be carried out by that receiver.
The top line in FIG. 2 represents the operating condition of the
receiver 30. During the period designated by W, the receiver 30 is
in an operating condition "WATCH" or watching mode, wherein the
receiver 30 is alternately in an ON state for a predetermined
period of time T.sub.ON and in an OFF state for a predetermined
period of time T.sub.OFF with a predetermined repetition period.
During the OFF state, a receiving unit of the receiver 30 is
switched OFF, so that it consumes hardly any energy. During the ON
state, that receiving unit of the receiver 30 is switched on, and
incoming signals, if any, are processed and assessed. If the
receiver 30 does not recognize therein a command intended for the
relevant receiver 30, that receiver 30 returns to the OFF state
again after an ON period had ended, to reach the ON state again
only after the predetermined period of time T.sub.OFF. This return
to the OFF state upon expiry of the ON period always occurs in the
absence of a transmitted signal, as is illustrated in FIG. 2 during
the interval Q, but also when an incoming signal is a background
signal or a signal deformed by disturbances, or a signal intended
for another receiver.
If the receiver 30 during the ON state recognizes a transmission
command at the period of time t.sub.3, the receiver 30 ends up in
an operating mode "RECEPTION", or receiving state, as is indicated
by the interval R in FIG. 2. During this receiving state, the
receiver 30 carries out the received command through the emission
of a suitable signal to the above-mentioned motor in order to
energize this motor in a desired manner. The receiver 30 remains in
this receiving state R as long as the transmitting pulses P are
recognized, and this motor remains energized all that time. To the
user, this means that a change of the position of the slate 12
takes place as long as he keeps a button depressed. As soon as the
user is satisfied with the reached position of the slats 12, he
releases that button. Accordingly, the receiver 30 no longer
receives any pulses P and terminates the energization of the motor
60, as illustrated by the bottom line in FIG. 2, representing the
energizing state of the motor 60.
Maintenance of the ON state of the receiver 30 during the receiving
state implies that the receiver should in each case check the
received signal. In accordance with an aspect of the invention,
that check preferably does not take place continuously, but at
intervals, as is illustrated diagrammatically in FIG. 5, where the
top line illustrates the operations of the receiver 30. In the
Figure, the check periods are indicated as CHECK, and the
intermediate periods as WAIT. In principle, the motor 60 can be
energized by the receiver 30 during the CHECK period as well as the
WAIT period, i.e. a truly continuous energization. In accordance
with a preferred aspect of the present invention , however, the
motor 60 is energized intermittently, with the energizing period of
the motor, which period is indicated by POWER, coinciding with the
WAIT period of the receiver, as is indicated by the bottom line in
FIG. 5. This yields the advantage that the motor is not energized
when the receiver 30 checks the received signal. When a battery is
used as power source, a motor forms such a load to that source that
the source voltage could drop, in particular when the battery is
almost empty, to such a low value that the receiver could no longer
function properly; this problem is avoided by the solution
described.
Suitable values for the duration of the CHECK period and the POWER
period are about 13 ms and about 43 ms respectively.
In principle, at the point of time t.sub.2, the receiver 30 can
directly return to the watching state W. In accordance with a
preferred variant, however, the receiver remains in a waiting state
until a point of time t.sub.4, as indicated by the interval U in
FIG. 2 and as further illustrated in FIG. 5, wherein the receiver
30 is active but no longer generates an energizing signal for the
motor 60. Hence, this waiting state is comparable with the ON state
during the watching mode, but only occurs after the operating mode
"RECEPTION" has ended. One reason for this waiting state U is to
make allowance for short interruptions in the transmitted signal,
for instance because the user releases the button for a moment,
consciously or unconsciously, and when the tramsmitted signal is
resumed within the waiting state U, the receiver 30 reacts
directly. Another reason is to enable the user to position the
slats 12 accurately by depressing the button briefly and releasing
it again. The duration t.sub.4 -t.sub.2 for instance about 2
sec.
Preferably, the period of time T.sub.ON of the receiver 30 is
chosen in relation to the pulse length T.sub.P of the transmitting
pulses, according to the formula T.sub.ON >T.sub.P, to allow the
receiver 30 time to process an incoming signal pulse. However, the
exact moments at which a transmitting pulse P begins are not known
at the end of receiver 30, and hence it is possible that a
transmitting pulse P only partly coincides with the ON period of
the receiver 30. The receiver 30 according to the invention has
been designed to avoid this problem.
In a first structural variant, the period of time T.sub.ON of the
receiver 30 is chosen in relation to the pulse repetition period
T.sub.R and to the pulse length T.sub.P of the transmitting pulses,
according to the formula T.sub.ON >T.sub.R +T.sub.P, to
guarantee that if the transmitter transmits pulses P, an ON period
of the receiver 30 always contains at least one complete
transmitting pulse P, regardless of the phase of the pulses
relative to the ON period.
A second structural variant is based on the fact that for
transmitting the pulses P, a carrier wave of a predetermined
frequency is used; in a preferred embodiment of the remote control
system according to the present invention, infrared light is used
therefor. The invention provides a two-phase detection by the
receiver 30, wherein the presence of a carrier wave is checked in a
first phase and the presence of transmitting pulses is not checked
until a second phase. If the carrier wave between two successive
pulses P from the transmitter 20 is suppressed, then the switch-on
time T.sub.ON, 1 of the receiver in the first phase can be chosen
in relation to the pause time between two successive pulses P,
according to the formula T.sub.ON, 1 >T.sub.R -T.sub.P, so that
in the presence of pulses, at least a portion of a pulse coincides
with the switch-on time T.sub.ON, 1. If the carrier wave between
two successive pulses P from the transmitter 20 is not suppressed,
then the switch-on time T.sub.ON, 1 of the receiver in the first
phase can be chosen to be still shorter, viz. as short as is
minimally required for establishing the presence of a carrier wave
signal. If the receiver does not detect a carrier wave signal in
the first phase, which is indicative of the absence of transmitting
pulses P, then the receiver 30 can return again into the OFF state
directly after the switch-on time T.sub.ON, 1 has ended.
If during the switch-on time T.sub.ON, 1 the receiver does detect
the presence of a carrier wave signal, then the ON state is
prolonged in the second phase to the aforesaid T.sub.ON, to check
the presence of recognizable transmitting pulses P, as is described
hereinabove. Because the switch-on time T.sub.ON, 1 can be
considerably shorter than the aforesaid T.sub.ON, in this manner,
an additional energy-saving of the receiver is possible.
It is observed that the motor is not energized during the time when
the receiver is in the ON state without it having been established
whether a command is being received. Since, for that purpose, at
least one complete transmitting pulse P should first be received
and analysed by the receiver, some time delay occurs in practice
between the moment when the receiver, still in the "WATCH" mode,
ends up in the ON state and the moment when the receiver shifts to
the "RECEPTION" mode and the motor is energized; this time delay is
not shown in FIG. 2.
Presently, with reference to FIG. 3A-B, an example will be
described of a coding, found suitable, of the transmitted signals,
each transmitting pulse P containing digitally coded information.
The information is sent by means of infrared light. FIG. 3A
illustrates the distribution of the information over a transmitting
pulse P; each transmitting pulse P contains a header A of a
duration of about 1.4 ms, and then eight bits B1 through B8 each of
a duration of about 0.9 ms, the meaning of which will be explained
later on. Thus, in this example, the pulse length T.sub.P is
approximately equal to 8.6 ms. After each pulse P there follows a
pause C of a duration of about 10 ms. Hence, in this example, the
repetition period T.sub.R is approximately equal to 18.6 ms, which
corresponds with a repetition frequency f.sub.R of about 54 Hz.
Each bit signal B1 through B8 is subdivided into two successive bit
halves BH1 and BH2, only one of which contains a square-wave signal
B; the other bit half is hence free of signal. The square-wave
signal B consists of square waves of infrared light, which square
waves have a repetition frequency of about 38 kHz with a duty cycle
of 33%.
The pause C is entirely free of signal. The header A is completely
filled with the square-wave signal B and serves as a
synchronization signal for the receiver 30.
Each bit signal B1 through B8 is indicative of either a logical 0
(zero), or a logical 1 (one). If a bit signal is indicative of a
logical 0, then the first half BH1 of that bit signal is filled
with the square-wave signal B and the second half BH2 thereof is
empty. If a bit signal is indicative of a logical 1, then the first
half BH1 of that bit signal is empty and the second half BH2
thereof is filled with the square-wave signal B. It will be
understood by a skilled person that another unequivocal coding is
also possible.
In this manner, in each pulse P a binary word of eight bits B1
through B8 is transmitted. The meaning of these eight bits in this
example is as follows:
______________________________________ B1: start bit of value 1;
B2, B3, B4: group code: B5, B6: address code; B7: data bit B8:
check bit. ______________________________________
The check bit B8 has a value which depends on the values of the
bits B1 through B7, and is intended to perform a so-called parity
check.
The data bit B7 determines the direction of rotation of the motor
to be operated.
With the address defined by the bits B5 and B6, which address can
hence have the values 0-3, maximally four different blinds or
groups of blinds can be individually controlled. In a preferred
embodiment, the address 1-3 are intended to control three different
blinds or groups of blinds individually, and the address 0 is
intended to control all blinds jointly.
With the group code defined by the bits B2 through B4, which group
code can hence have the values 0-7, the appliances to be controlled
can be divided into specific groups of appliances. This enables
determination whether a code is only intended for the group of
blinds having vertical slats, or for the group of blinds having
horizontal slats, or for groups of possible appliances to be
further defined.
It will be understood by a skilled person that in principle, the
number of bits to be transmitted can be chosen at will. For
instance, if it is desired to operate more than three groups of
different blinds individually, the number of address code bits can
be increased. It is also possible to choose the number of group
code bits to be two and the number of address code bits to be
three.
Further, in this example, the ON time T.sub.ON of the receiver is
chosen to be about 28 ms, to ensure that if the pulses P are
transmitted as mentioned hereinbelow, during that ON time T.sub.ON,
at least one complete transmitting pulse P occurs. In the watching
state, the receiver is controlled with a repetition code of about
580 ms, so that the OFF time T.sub.OFF is about 552 ms.
With reference to what is discussed hereinabove, it will be
understood that the reaction time of the system 1, i.e. The time
passing between the moment t.sub.1 when the user depresses a button
and the moment t.sub.3 when the receiver 30 reacts with an
adjustment of the slats 12, is in the most unfavorable case about
600 ms at the most, which is in every way acceptable. Further, it
will be understood that on average, during the watching state, the
receiver 30 is switched on for 4.8% of the time, which yields an
energy-saving of a factor 20. It will be understood that the
energy-saving realized can be further increased by choosing a
shorter bit time or a longer OFF time.
FIG. 3B shows a block diagram of a transmitter 20 with which
infrared light pulses P with the above-mentioned coding can be
generated. The transmitter 20 comprises a control unit 41 and an
output element 42, of which a control input 43 is connected to a
control output 44 of the control unit 41, which may for instance be
a suitably programmed microprocessor. The control unit 41 has an
input bus 45 which is connected to the buttons 22, 23, 24, 25.
The output element 42 has an output 46 which is connected to an
infrared light-emitting diode LED 47, of which the emitted light
leaves the housing 21 via an aiming lens 26. Depending on the
voltage level at its control input 43, the output element 42 is
either in a transmitting mode or in a silent mode. In the
transmitting mode, the square waves B are transmitted; in the
silent mode, no light is emitted. In this example, the output
element 42 is in the transmitting mode if the level at its control
input is high (H), while the output element 42 is in the silent
mode if the level at its control input is low (L).
If none of the control buttons 22-25 is depressed, the control
output 44 of the control unit 41 is low. The control unit 41 is
adapted to supply a repeating series of control signals to its
control output 44 if one of those control buttons is depressed,
each control signal being built up as follows:
A: a high level with a length of 1.4 ms;
B: eight successive bit control signals BS1 through BS8 with
lengths of 0.9 ms;
C: a low signal with a length of 10 ms.
Each bit control signal BS1-BS8 is a high/low signal or a low/high
signal, as will be understood by a skilled person. Which of the bit
control signals BS1-BS8 is a high/low signals and which are
low/high signals is determined by the control unit 41, depending on
the control button depressed and on a table stored in a memory 48
of the control unit 41.
It will be understood that it is also possible to program a control
unit 41 such as a microprocessor so that the control unit 41 itself
generates the required voltages for the LED 47, while an amplifier
stage for the LED 47 may further be present, if desired. It will be
understood by a skilled person which commercially available
electronic building blocks are suitable for the above-discussed
components 41 and 42. It will also be understood by a skilled
person that it is possible to design a different circuitry
exhibiting the above-discussed behavior, for instance with discrete
components.
In the above-described example, the information in the transmitted
signal is coded on the basis of the presence and absence of a base
wave. However, it is also possible to use another coding protocol.
For instance, it is possible to code the information in the
transmitted signal on the basis of the use of frequency changes in
a base wave. In that case, for instance, a signal of a first
frequency may represent a logical "1", and a signal of a second
frequency may represent a logical "0", while successive bits in a
sequence to be transmitted may be separated by a third
frequency.
Presently, with reference to FIG. 4, an example will be discussed
of a receiver 30 intended for use with the transmitter discussed
with reference to FIG. 3A-B. The receiver 30 comprises a
signal-receiving and decoding section 31 and a control means 50.
The signal-receiving and decoding section 31 comprises a detector
33, for instance a diode sensitive to infrared light and of a type
known per se, which, at an output 34, provides an electric signal
corresponding with the light signal received.
The output 34 of the detector 33 is connected to an input 35 of a
converter 36 adapted to convert the output signal of the detector
33 into an 8-bit digital signal, which signal is provided in serial
form at an output 37.
This output 37 is connected to an input 51 of the control means 50
which is adapted to process the input signals received at the input
51. The control means 50 has supply terminals 52, 53 which are
connected to an exchangeable battery 54 of a suitable type, and is
adapted to switch, via a control output 55, the signal-receiving
and decoding section 31 ON and OFF with a predetermined regularity.
This may be effected by providing the signal-receiving and decoding
section 31 with supply voltage with that regularity, the control
output 55 then being a supply output, or by controlling the
components 33, 36 of the signal-receiving and decoding section 31
to an ON state or OFF state respectively, the control output 55
then being a control signal output, as will be understood by a
skilled person.
The control means 50, which may be a suitable programmed
microprocessor, is adapted to make an ON state last a first
predetermined time (for instance 28 ms), and to compare, during
that first predetermined time, signals received at the input 51
with a code stored in a memory 56, which code may consist of five
memory bits M2 through M6, and to determine on the basis of those
received signals whether the ON state is ended or continued.
If no or no valid signal is received, or if comparison of the
received bits B2-B6 with the memory bits M2-M6 proves that the
received signal is not intended for this receiver 30, then the ON
state is ended after expiry of the first predetermined time, and
switched on again only after a second predetermined time (for
instance 560 ms).
The control means 50 is further adapted to maintain the ON state
for a third predetermined time of at least 20 ms if comparison of
the received bits B2-B6 with the memory bits M2-M6 proves that the
received signal is indeed intended for this receiver 30. Further,
the control means 50 is adapted to prolong the ON state by that
third predetermined time as long as comparison of the received bits
B2-B6 with the memory bits M2-M6 proves that the received signal is
indeed intended for this receiver 30, and to energize the motor 60
coupled to the tilting-operating mechanism of the slats 12 during
that time. To that end, output terminals 57, 58 of the control
means 50 are connected to supply terminals of the motor 60, and the
control means 50 is adapted to connect the output terminal 57 to
the input terminal 52 and to connect the output terminal 58 to the
input terminal 53, or to connect the output terminal 57 to the
input terminal 53 and to connect the output terminal 58 to the
input terminal 52, depending on the desired direction of rotation
of the motor 60 as determined by the value of the received bit B7.
In addition, the control means 50 is adapted to limit the current
through the motor 60 to a predetermined maximum value so as to
limit the maximum torque producible by the motor 60 at its output
shaft. This prevents damage to the mechanism if, by some cause, the
slats 12 cannot tilt when the motor 60 is energized, for instance
because they have reached their extreme position. Normally, limit
switched are used for this purpose, but these are relatively
expensive and require space and additional wiring.
The above process repeats itself as long as the signal received at
the input 51 corresponds with the same code, during which time the
motor 60 remains energized, preferably intermittently, as mentioned
above. The control means 50 is adapted to disconnect the connection
of the output terminals 57, 58 to the input terminals 52, 53 if the
signal is no longer received or if the received code B2-B6 changes,
but to maintain the ON state for a fourth predetermined time, for
instance 2 sec, and to end it if still no signal or "proper" code
is then received.
The code M2 through M6 in the memory 56 can be set by means of
hardware, for instance by setting five switches or jumpers. This
can be carried out by the supplier or by the user. In a preferred
embodiment, however, the code M2-M6 is set by means of software
through the control means 50. The memory 56 can be a RAM memory
with at least 6 memory locations M1-M6, the memory location M1
being a check location. If a valid code is stored in the RAM memory
56, the value of the check location M1 is a logical "1"; if the
code is absent or invalid, M1 is a logical "0". For changing the
code, the control means 50 can be provided with a reset switch, not
shown, and the control means 50 can be adapted to make the value of
M1 equal to "0" in response to the reception of a reset signal.
Also when voltage of the battery 54 is interrupted, the value of M1
becomes equal to "0", just as the value of M2-M6; the RAM memory is
erased upon removal of the battery.
In this embodiment, the control means 50 is adapted to read the
memory location M1 first. If the value thereof is "1", the
above-described operations are performed. However, if the value
thereof is "0", the control means 50 copies the value of the
received bits B2-B6 to the memory locations M2-M6, and writes the
value "1" in the memory location M1. If the value of the bit b1 is
"1", as mentioned above, the control means 50 can also simply copy
the value of the received bits B1-B6 to the memory locations
M1-M6.
As a result, the receiver 30 is "self-learning", which means an
increased control convenience. Then, when a blind has just been
installed (or reset), a user can determine in a quick and simple
manner to which button on his remote control this blind should
react in the future, by transmitting a command with that button.
The receiver reads the first incoming addressing in the received
signals and records this addressing in its memory, and henceforth
considers this to be "its own address".
The operation of this preferred embodiment will be discussed in
more detail with reference to the flow diagram of FIG. 6. First,
the steps for receiving the data bits will be described with
reference to the right-hand flow diagram in FIG. 6 (subroutine
100).
In step 101, it is checked whether a correct header A has been
received. If not, subroutine 100 is ended with an error flag set
(step 102).
If a correct header A has been received, a data bit is read in at
step 103, and this step 103 is repeated (step 104) until 8 data
bits have been read in. Next, at step 105, a parity check is
carried out. If an error is detected, subroutine 100 is ended with
an error flag set (step 106).
Next, at step 110, the memory 56 is examined. The memory 56 can be
formed by a fixed hardware setting, for instance of switches or
jumpers, in which case the first bit M1 of the memory 56 will
always be set at "1". The memory 56 can also be formed by memory
locations in a RAM memory. If it appears at step 110 that the
memory 56 is empty, at least that the first bit M1 of the memory 56
is "0", then, at step 111, the memory bits M1-M6 of the memory 56
are made equal to the received bits B1-B6, with B1 being "1". If it
appears at step 110 that the memory 56 contains a valid code (group
code and address code), at least that the first bit M1 of the
memory 56 is "1", then step 111 is skipped.
Next, at steps 121-123, it is determined whether the addressing
(group code and address code) contained in the received bits B1-B6
corresponds with the addressing recorded (by means of hardware or
software) in the memory 56 or with a general coding (step 121). If
that is not the case, either because the group code does not
correspond with the group code recorded in the memory 56 (step 124)
or because the address code does not correspond with the address
code recorded in the memory 56 (step 125), then the received
command is not intended for the receiver 30 in question, and the
subroutine 100 is ended with an error flag set. If the received
command is indeed intended for the receiver 30 in question, then
the direction of rotation of the motor 60 is determined in
accordance with the value of the data bit B7 (step 126), and
subroutine 100 is ended without an error flag (step 127).
The flow diagram in the left half of FIG. 6 illustrates the
operation of the control means 50.
At step 200, the operation of the control means 50 starts. Through
the interrogation of a special status bit, it is first checked, at
step 210, whether this is the first time that the control means
operates after interruption of the supply voltage (POWER UP), in
which case, at step 211, the memory 56 is erased; if not, step 211
is skipped.
At step 220, the signal received at the input 51 of the detector 33
is observed, and at step 221 it is determined whether this is a
valid control signal. If not, it is examined at step 222 whether
the present time T.sub.ON has meanwhile lapsed; if this is not yet
the case, step 220 is proceeded with; if this time T.sub.ON has
indeed lapsed, the device returns into the rest position at step
223.
When, at step 221, it appears that a valid control signal is
received, then subroutine 100 is carried out to decode the control
signal. When this subroutine has ended, the error flag is examined
at step 230 to check whether that signal contains a command
intended for the receiver 30 in question. If that is the case,
then, at step 231, the motor 60 is energized according to the
desired direction of rotation, which energization is maintained at
step 232 for a preset time (the period POWER in FIG. 5. If that
preset time (for instance about 43 ms) has lapsed, then, at step
233, the motor is switched off again and step 220 is returned to in
order to examine the control signal again (the period CHECK in FIG.
5). To this end, this examining step 220 contains a relatively
short wait loop, not shown separately for the sake of simplicity,
to give the supply voltage an opportunity to recover from the load
formed by the motor 60.
If, at step 230, the received signal does not prove to contain a
command intended for the receiver 30 in question, then step 222,
mentioned before, is proceeded with.
It will be understood by a skilled person that it is possible to
alter or modify the embodiments shown of the apparatus according to
the invention without departing from the scope of the invention as
set forth in the claims. For instance, it is possible that the
blind has vertical slats which are rotated about their body axes.
Further, it is possible that the receiver with the motor is
attached to the headrail of the blind on the outside of the
headrail, rather than on the inside thereof.
As a variant of the example discussed with reference to FIG. 3A-B,
it is also possible to have the group code consist of two bits and
to have the address code consist of three bits, if it is desired to
be able to control up to maximally eight blinds independently of
each other. Further; it will be understood that, if so desired, it
is possible to use a dataword of more or less than eight bits.
* * * * *